The invention concerns a switching equipment for a transmission with load distribution on two countershafts.
With a gear shift transmission with load distribution on several countershafts, with a coaxial drive shaft that is mounted radially and axially, and with an output shaft (main shaft), that is mounted floating, whereby at least one drive gear wheel provided on the drive shaft passes torque to gear wheels meshing with it and connected tightly with the countershaft. The idler wheels are axially fixed to the drive and output shaft, but are radially free.
With transmissions of this type, with at least two countershafts, the load balancing is generally configured in such a way that the drive shaft and the countershafts are mounted rigidly in relation to the housing while the main shaft or output shift is mounted floating radially on the gear wheels allocated to it, which is situated in the flux of force, and is only axially fixed into position. Basically, however, the converse construction or shaft guidance is also possible. If torque diminishes on only one countershaft, which is usually the case with an auxiliary output connection, radial and axial forces arise on an inclined geared gear engagement on the drive shaft. In order to be able to absorb these, the gear wheel situated in the flux of force must be guided to the drive shaft. All idler wheels on the drive shaft and on the output shift are only axially fixed into position, but are radially free for a functioning load compensation. The necessary load compensation is disturbed or a functioning of the gearshift transmission is not possible at all if an asymmetrical power application occurs. This is, for example, the case if an auxiliary output is to take place over only one countershaft.
A shiftable radial fixation for a constant gear wheel is known from DE 43 05 103 A1 in which the switching equipment which introduces the constant gear wheel into the torque flux also contains a device for a radial fixation of the shifted constant gear wheel. The switching equipment nonetheless only permits a radial fixation and use of the first constant because the shaft deflection of the drive shaft becomes too great with an operation over the second constant.
Underlying the invention is the objective of enabling the drive of an auxiliary output through the second constant.
The switching equipment of the invention for a transmission with load distribution on two countershafts has two constant gear wheel trains. At least one of the constant gear wheel trains serves for the transmission of torque which is introduced into the transmission to that countershaft on which the auxiliary output is arranged. The switching equipment, furthermore, has a synchronizing apparatus. The constant gear wheel trains have three gear wheels, two of which are arranged on the countershaft, while the third gear wheel is arranged axially fixed but radially mobile on the input shaft or the output shaft of the transmission. The gear wheel of the second constant gear wheel train not arranged on one of the countershafts is fixed radially in a clutch apparatus such that the clutch apparatus permits radial play of the gear wheel in relation to the shaft on which the gear wheel is arranged. In an especially advantageous refinement, an Oldham type clutch is provided between the synchronization apparatus and the gear wheel of the second constant gear wheel train which is not arranged on one of the countershafts.
If the torque introduced into the transmission, through the switching equipment, is shifted from the input shaft of the transmission to the gear wheel of the second constant gear wheel train that is not mounted on one of the countershafts, then the two tooth flanks of the teeth engaging, in any given case, are braced upon the tooth flanks of the corresponding matching gear wheels of the countershafts. Through the radial fixation of the gear wheel of the second constant gear wheel train in the clutch apparatus, the gear wheel can no longer fall back radially. The gear wheel of the first constant gear wheel train which is not arranged on the countershaft forms a coupling member owing to its radial mounting between the two countershafts, and in this way the result is a form-locking feedback coupling of the countershaft, to which the auxiliary output is connected, on the opposite-lying and previously unstressed countershaft. As a consequence of this feedback coupling, the gear forces of the gear wheel of the second constant gear wheel train is distributed to both countershaft equally by halves and carried back again to the countershaft to which the auxiliary output is connected. The complete torque is therewith available on the countershaft to which the auxiliary output is connected.
In one embodiment, driving noses are provided on the gear of the second constant gear wheel train which engage into a slide ring on the Oldham type clutch, and in one refinement, driver noses are also arranged in a coupling element of the synchronizing apparatus which engage with the slide rings on the Oldham type clutch. In a further advantageous embodiment, a disk joint is provided between the synchronizing apparatus and the gear wheel of the second constant gear wheel train which is not arranged on one of the countershafts. In one embodiment, the driver noses are provided on the gearwheel of the second constant gearwheel train which engage into disks and chain members of the disk joint, and in one refinement, driver noses are also arranged on a coupling element of the synchronizing apparatus that engage into the disks and chain members of the disk joint. In one construction, the synchronization apparatus is provided as a bolt synchronization, and the clutch gearing is arranged between the bolt synchronization and the gear wheel of the second constant gear wheel train which is not arranged on one of the countershafts, is constructed such that positioning inexactitudes between the gearings of the first and second constants are balanced. An advantageous embodiment has a needle-mounted gear wheel of the first constant gear wheel train (which is not arranged on one of the countershafts) on the input shaft.